The United States, Britain and Japan on Thursday sent congratulatory messages to Manmohan Singh on his appointment as prime minister and hoped their relations with India would be further strengthened.

Felicitating Singh on his appointment to the top post, US Ambassador David Mulford said the US and India have a strong bilateral relationship based on their democratic values and shared interests.

"The US looks forward to working with Singh and his government to further strengthen this relationship. I am confident that progress in US-India relations will continue to be positive," he said in a statement in Delhi.

Wishing Singh all success in the challenges ahead, Britain said that India's pluralist democracy is a role model for its neighbours and partners in South Asia.

"No one can fail to be impressed by the power of a democracy where over 380 million people can bring about a peaceful transfer of power through the ballot box. India's pluralist democracy is a role model for her neighbours and partners in South Asia," British Foreign Secretary Jack Straw said.

"And all of us in the British Government wish the incoming Indian United Progressive Alliance government, which will be led by architect of India's economic reforms, Manmohan Singh, every success in the challenges ahead," he said at the Commonwealth Business Council in London last night.

Japanese Prime Minister Junichiro Koizumi looked forward to working with Singh 'with a view to developing the cordial relationship to a newly enhanced level'.